sedimentary

Jasper with Agate Inclusions

Jasper (Silicon Dioxide, SiO2) with Chalcedony/Agate

Hardness: 6.5-7 on Mohs scale; Color: Red, brown, and translucent white; Luster: Vitreous to waxy (especially when polished); Crystal Structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.91.

Hardness: 6
Color: Red, brown, and translucent white
Luster: Vitreous to waxy (especially when polished)

Identified April 13, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the infiltration of silica-rich fluids into volcanic or sedimentary rock cavities. Often associated with rhythmic precipitation of iron oxides and silica during the cooling of hydrothermal fluids.

Uses & applications

Primarily used for lapidary work, jewelry (cabochons), interior decoration, and as a popular semi-precious gemstone for mineral collectors.

Geological facts

Jasper is an opaque variety of chalcedony. When it shows translucent 'windows' or banding like this specimen, it is often called 'Agatized Jasper'. Red coloration typically comes from iron inclusions (hematite).

Field identification & locations

Identify in the field by its hardness (cannot be scratched by a steel knife), smooth conchoidal fracture, and opaque to semi-translucent patterns. Commonly found in riverbeds and volcanic regions in Oregon, Idaho (USA), Brazil, and Madagascar.

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